题目
2、设X_(1),X_(2),X_(3),X_(4)是来自总体Xsim N(0,1)的样本，X=a(X_(1)-2X_(2))^2+b(3X_(3)-4X_(4))^2总体服从X^2分布，则a和b的取值为( ).A. (1)/(5),(1)/(25)B. (1)/(5),(1)/(5)C. (1)/(25),(1)/(5)D. (1)/(25),(1)/(25)
2、设$X_{1},X_{2},X_{3},X_{4}$是来自总体$X\sim N(0,1)$的样本，$X=a(X_{1}-2X_{2})^{2}+b(3X_{3}-4X_{4})^{2}$总体服从$X^{2}$分布，则a和b的取值为( ).
A. $\frac{1}{5},\frac{1}{25}$
B. $\frac{1}{5},\frac{1}{5}$
C. $\frac{1}{25},\frac{1}{5}$
D. $\frac{1}{25},\frac{1}{25}$
题目解答
答案
A. $\frac{1}{5},\frac{1}{25}$